More XP from mobs

I Have mending on all my tools and armore and on the server i am playing on we haven't opened the end yet. And to repair my tools i  have a simple zombie spawner. but it is super slow. And i came up with the idea of an enchantment that makes it so you get more xp from killing mobs. I think this is a good idea because when you need this enchantment you already have some good tools and armore. and then it takes a lot of time to repair the tools because they have so much durability. this will help people that are going to enchant there stuff to. Because then you need a lot of levels to get the perfect set of tools and armore. and this takes to much time. For me I just want my tools done so I can get to building.